The present invention relates to grinding machines particularly for grinding the blades of knives after hardening in order to give the same their cutting edge, or after finishing operations to give the blades their final sharpening, or to effect the thickness calibration simultaneously of the two sides of a similar or corresponding member.
In the known machine for this type of work, the facing grinding wheels receive between them the blade to be ground by means of a blade holder mounted on an arm, positioned in front of the wheels and controlled by slides moved by different hydraulic or mechanical means and aligned with the arm in front of the wheels.
In this arrangement, the copying template of the profile to be made cannot be placed flush with the blade because it would receive the spraying liquid containing the suspended abradant and the metal particles from the grinding process. Therefore, in general, the template is placed between the blade holder and is therefore marked out with a different relationship from that of the considered blade profile. As a function of its spacing or remoteness point, this outline can only be empirical and imprecise relative to the true curvatures of the blade to be made, which is disadvantageous with respect to the precision of reproduction of the profile in question.
Another disadvantage is based on the fact that the free space in front of the grinding wheels is occupied by the arm and its slide, so that it is impossible to fit a revolving-type multiple blade holder. The blade is replaced when the grinding operation of the preceding blade is finished, thus increasing the machine cycle time by the time required for loading the workpiece.
Moreover, spraying liquid containing abradant and metal powder splashes and is deposited on the wheel-regulating slides, located below the work point, which causes premature wear of said slides.
Finally, on such machines, the controls are distributed over several different members which makes the same both complicated and imprecise.